Many industrial processes, such as mineral processing, petroleum refining, chemical engineering, food processing, and environmental cleaning, require the removal of particulate matter from an air stream. The present invention relates to gas cyclone separators for separating particulate material from a gaseous medium. Cyclone separator is widely used for its main advantages of simple structure and low cost. A common type of cyclones is the so-called “reverse flow” cyclones where particle-rich gas can be withdrawn from the tangential inlet of the cyclone body, while clean gas essentially reverses flow from its initial path toward the end of the cyclone body, back toward the vortex finder (the gas outlet). The gas outlet is a tube normally located within the cyclone body. In this type of cyclone, particles are separated based on the balance between inertial and fluid forces acting on the particles in a flow field.
Therefore, this type of cyclone generally has low separation efficiency for fine particle or particles whose density differs very little from the density of the fluid. The present invention provides a cyclonic separator with improved efficiency for removal of fine and light particles from air streams.
JP02003038398A discloses a cyclone type vacuum cleaner. Dust is separated through two filters: a cylindrical filter and a filter bag. A rotary brush is arranged at the outer surface of the cylindrical filter, which is different from the present invention. The cylindrical filter is closed and air can only flow through the outer side surface of the cylindrical filter into the center of the cylindrical filter and then goes to the filter bag. The direction of the air stream flowing through the cylindrical filter is opposite to the design of the present invention.
JP02004249068A discloses a cyclone dust collecting device of a vacuum cleaner. The cyclone is in a cylindrical shape, which is different from the present design where the cyclone comprises an upper cylindrical part and a lower conical part. The direction of air flowing through the rotating filter which is in the center of the cyclone body is opposite to the cyclone described herein. Further, there is no brush used in the cyclone dust collecting device.
JP 2003310507 discloses a dust collector and a vacuum cleaner. A cyclone type box is inserted and located in a cleaner main body. The cyclone type box is not present as a combination of a cylindrical and a conical part. There is no double vortex formed within the box.
JP2003038397 discloses a cyclone type dust collector having a filter brushing mechanism. This cyclone type dust collector has no conical part. The rotating brush is to clean the outer surface of the filter.
U.S. Pat. No. 6,824,580 B2 discloses a cyclone dust collecting apparatus for a vacuum cleaner including a cyclone body, a flexible dust receptacle (or bag), a grill assembly and a contaminant removing unit. The spiraling air is formed within the flexible dust receptacle rather than in the cyclone body. The grill assembly includes longitudinal slots which are used to filter out containments and the contaminant removing member moves up and down.
U.S. Pat. No. 6,928,692 B2 is similar to U.S. Pat. No. 6,824,580 B2 but makes a major modification to the grill assembly. A rotating brush is arranged outside the grill assembly.
U.S. Pat. No. 3,979,194 discloses a cylindrical dust filter for placement on the exhaust cylinder of a dust collector. This device collects dust without the use of centrifugal forces and is placed on the gas exit of a dust collector.
United States Patent Publication No. 20040200029 discloses a filter assembly for a cyclone-type dust collecting apparatus of a vacuum cleaner which filters the dust included in the air current discharged from the outlet port of the cyclone-type dust collecting apparatus. Concerning the cyclone-type dust collecting apparatus, the cyclone body does not include an upper cylindrical part and a lower conical part. This filter assembly does not use centrifugal forces to separate particles. Within the filter assembly, a brush is placed to brush the outer surface of the filter and the filter is rotary, which are different from the present invention, in which the brush is arranged to brush the inner surface of the filter and the filter is not rotary. The filter is in a wave shape in the present invention.
United States Patent Publication No. 20040187253 discloses a filter cleaning device which comprises a cyclone body, a dust collecting receptacle and a filter. This filter cleaning device is similar to the disclosures of U.S. Pat. No. 6,928,692 B2 and U.S. Pat. No. 6,824,580 B2 except for the filter. The brush is placed to brush the outer surface of the filter and moves up and down.
United States Patent Publication No. 20040177471 A1 discloses a similar design to the disclosures of US20040187253, U.S. Pat. No. 6,928,692 B2 and U.S. Pat. No. 6,824,580 B2 except the filter assembly. Again, brush is placed outside of the filter and moves up and down.
United States Patent Publication No. 20060042202 discloses a dust collection unit for a vacuum cleaner. This unit consists of a cylindrical part only without the conical part. The direction of air flowing through the filter is opposite to the present design. The brush is positioned in such a way as to brush the outer surface of the filter and the arrangement of brush is different from the device disclosed herein.
U.S. Pat. No. 5,271,751 discloses a device for removing dust from a work processing machine and more particularly from a floor sanding machine. The dust separator is preferably in the form of a centrifugal separator. The gas outlet of this dust separator is a simple cylinder. In the present design, the gas outlet (which is called vortex finder in this invention) was replaced by a dual-layer filter and a rotary brush.
U.S. Pat. No. 6,090,183 discloses a method for processing an exhaust gas produced during manufacturing of semiconductor devices. In this invention, a rotating brush is used to remove the fine particles accumulated on the wall of the processing chamber. There is no gas cyclone or filter disclosed in this patent.
U.S. Pat. No. 5,922,092 discloses a system for gasification of a wide range of solid organic materials to yield a useful product gas output. In the mechanical cleaner, gas stream is introduced to the bottom and exits at the top of the cleaner. Further, the conical part is placed above the cylindrical part. There is no double vortex flow pattern in the cleaner.
United States Patent Publication No. 20010025395 discloses an electric vacuum cleaner. In this disclosure, the dust collection chamber is cylindrical and there is no double vortex flow pattern for air stream. The brush is placed at the outer surface of the filter.
JP8182910 discloses a dust removal device for removal of oil content and water content from gas, which contains a cylindrical housing, a liquid separating device, a filter and a rotary brush.
U.S. Pat. No. 5,746,795 discloses a cyclonic air cleaning device, which includes a cylindrical-conical cyclone body, a barrel having a vortex tube concentrically positioned in the top cylindrical section and a cylindrical, pleated filter cartridge concentrically positioned within the vortex tube. This design does not contain a rotary brush, different from the present invention. The rotary brush in the present design can improve the separation efficiency of the cyclone separator and prevent particles from accumulating on the surface of the filter.
U.S. Pat. No. 6,739,456 discloses a particle classifier, comprising a housing, a boundary layer momentum transfer device, and an inlet flow control mechanism, for the classification of particles from a fluid stream via centrifugal separation imparted by boundary layers developed between rotating parallel disks. The rotational disks are stacked in spaced, parallel relation in the interior chamber. However, short circuit of gas flow may occur at the openings of the stacked disks.
The publication, Tomasz Chmielniak, Andrzej Bryczkowski, Method of calculation of new cyclone-type separator with swirling baffle and bottom take-off of clean gas—part I: theoretical approach, Chem. Eng. Process. 39 (2000) 441-448, teaches a cyclone-type separator with swirling baffle and bottom take-off of clean gas for separating solid particles from gases. The principal part of the cyclone-type separator is the cylinder-shape baffle with flow gaps cut on its surface, and the baffle is driven to rotate at different speeds by the motor placed on the top of the separator. When the dusty gas flows into the separator tangentially, most of the solid particles will be stopped by the swirling baffle while the clean gas passes through the flow gaps and flow out of the separator from the bottom.
The publication A. Bauder, F. Müller, R. Polke, Investigations concerning the separation mechanism in deflector wheel classifiers, Int. J. Miner. Process. 74s (2004) s147-s154, teaches a classifier with a rotating deflector wheel located inside. The feed material is transported by the gas to the deflector wheel with the rotating tip speeds up to 60 m/s for fine cut sizes. Because the influence of the centrifugal force is stronger than the drag force for the coarse particles, the coarse particles are rejected by the classifier wheel and sediment to the coarse outlet. However, for the fines, they leave the classifier with the gas stream through the deflector wheel because the influence of the drag force is dominant.
The publication J. J. H. Brouwers, Particle collection efficiency of the rotational particle separator. Powder Technol., 92 (1997) 89-99, teaches a rotational particle separator for separating solid and/or liquid particles from gases. The key component is the rotating filter element which consists of a multitude of axially oriented channels located in the cyclone body. Particles in the gas passing through the channels in a laminar fashion are centrifuged towards the outer collecting walls of each channel, and the clean gas leaves the channels at the exit.